1. Field of the Invention
The invention relates to touch sensing circuits, and in particular relates to touch sensing circuits for household products.
2. Description of the Related Art
Users usually operate electric equipment using man-machine interfaces (MMI). Generally, the man-machine interface comprises an input area and an output area. The input area is operated, such as turning on or off the electric equipment, according to a user's action. The turning on or off of the electric equipment by the man-machine interface can be achieved using mechanical or electrical means. A reliable control method identifies a touch event to control the electric equipment, avoiding operation error due to the aging of mechanical switches or objects interfering with photo-interrupt switches.
Conventional touch sensing circuits detect a touch event of a user using touch detection circuits, identify the electrical behavior of the circuit affected by the touch event by sensing circuits, and determine a location of the touch event, wherein a controller is used to perform corresponding operations.
However, the disadvantages of the conventional touch sensing circuits are circuit complexity and amount limitations dependent upon the number of input pins of a controller.
Thus, as man-machine interface product functions increases, for the issues of cost, there is a need for a touch sensing circuit with a simplified circuitry design and a high number of touch detection circuits.